The present invention relates generally to methods, systems and devices for performing corrective eye surgery. More particularly, the present invention relates to improved computer and laser system interface methods, computer interface programs, and operator system interfaces. The present invention is particularly useful for enhancing the speed, ease, safety, and efficacy of laser eye surgical procedures such as photorefractive keratectomy (PRK), laser in situ keratomileusis (LASIK), and the like.
Laser eye procedures typically employ ultraviolet or infrared lasers to remove a microscopic layer of stromal tissue from the cornea to alter its refractive power. Excimer lasers (i.e. ultraviolet laser), such as the VISX STAR™ or STAR S2™ laser system, use argon and fluorine gas to create a non-thermal laser light to break molecular bonds, in a process known as photoablation. Ultraviolet laser ablation results in the photodecomposition of the corneal tissue, but generally does not cause significant thermal damage to adjacent and underlying tissues of the eye. The photoablation removes stromal tissue to change the contour of the cornea to correct myopia (near-sightedness), hyperopia (far-sightedness), and astigmatism.
In general, existing laser eye surgery systems have included an operator interface for use by the laser system operator in setting-up, controlling, monitoring, and generally directing the laser treatment of the patient's eyes. The safety and efficacy of a photorefractive procedure depends in part on the operator's ability to interact with the laser control system using the operator interface. The costs of each surgical procedure are significantly affected by any unnecessary time delays in setting-up or directing the procedure. Unfortunately, existing operator interfaces are less than ideal in a number of aspects.
The photoablation of corneal tissues benefits from precise alignment between the eye and a therapeutic laser. Known laser eye surgical alignment systems typically have a patient seat or bed with the patient seated, lying down, or reclined in a supine position. To align the patient with the laser beam, the operator must manually adjust the seat or bed into alignment with the laser. Additionally, because the seat or bed often has limited speeds and/or ranges of motion the alignment procedure can be quite time consuming—especially when both eyes are to be treated.
Known operator interface display systems also suffer from a variety of additional disadvantages. For example, it may not always be as clear as would be desirable what type of refractive error and/or correction is represented on a controller display. Specifically, hyperopia and myopia designate alternative refractive errors which are opposite in nature, but it may not always be clear whether a negative value in a hyperopic display field designates a myopic characteristic or correction or a hyperopic characteristic or correction. An error introduced at this point would result in the patient's refractive error being doubled instead of corrected.
Laser ablation of the epithelial layer, an outer layer of the eye, is often performed before the re-sculpting ablation begins. While these epithelial ablations are now controlled from the operator interface, it can be time consuming to reconfigure the system if the epithelial layer is not completely removed from with the initial laser ablation treatment. Finally, known laser refractive surgery systems do not always provide sufficient information to everyone involved in the procedure. In addition to the system operator, the patient and assistant might benefit from procedure and/or system information which is currently directed only to the operator. These limitations detract from the speed, safety, and comfort of known refractive surgical techniques.
For these reasons, it is desired to provide an improved interface for laser eye surgery. In particular, it is desired to have a system capable of automatically aligning the patient's eye with the laser. Furthermore, it would be desirable to have a system which quickly and automatically aligns the patient's second eye after the first eye has been treated. It is also desired to have a system interface which would allow the operator to easily determine the refractive characteristics that have been entered. It would further be desirable to provide a system in which the assistant can view system information regarding the procedure, while still being near the patient. It would further be desirable if such a system could easily control the complete ablation of the target portion of the epithelial layer. At least some of these objectives will be met by the system and method of the present invention described hereinafter and in the claims.